Lead phosphate optical glass

ABSTRACT

NOVEL OPTICAL FLINT GLASS COMPOSITION ON A LEAD PHOSPHATE BASIS AND A METHOD OF MAKING THE SAME ARE DISCLOSED. THE COMPOSITIONS COMPRISE THE FOLLOWING INGREDIENTS: 20 TO 60 WT. PERCENT LEAD OXIDE (PBO), 30 TO 70 WT. PERCENT P2O5, AND 7.2-11 WT. PERCENT OF AT LEAST ONE OF THE OXIDES OF MAGNESIUM, CALCIUM, STRONTIUM, BARIUM AND ALUMINUM. THE GLASS COMPOSITIONS ARE CHEMICALLY RESISTANT, RESISTANT TO DEVITRIFICATION, STABLE TO WEATHERING AND CORROSION AND HAVE THE DESIRED TRANSMISSION IN THE SHORT WAVE LENGTH BLUE RANGE OF THE SPECTRUM.

United States Patent Oiice 3,585,057

Patented June 15, 1971 percent of lead oxide (PbO), 36.8 to 70 wt. percent of AD fi g gh GLASS P and 2.5 to 10.7 wt. percent of at least one of the LE t t b d Walter Jahn, Ingelheim, Germany assinor to JENaer gfigs ii calcmm S ton mm anum an N0 gg gg g i a g fgfg j'i gggf gh ia g gg 5 The glass compositions may additionally contain small Claims priority application Gel-many Sept. 8, 19 amounts of the conventional stabrlrzlng agents such as for J 31,733 example, boric acid and the alkali oxides.

Int. Cl. C03c 3/16 C] It has been found advantageous to melt the glass from a US Cl. 106-47 6 aims batch consisting wholly or partially of phosphates of the 10 metal oxides and preferably in the form of the metaphosphates as for example, of lead, aluminum and alkaline ABSTRACT OF THE DISCLOSURE earth l Novel optical flint glass compositions on a lead phos- The glasses of the invention differ 'e the P Y phate basis and a method of making the same are disknown lead Phosphate glasses 111 thell felahvely hlgh closed. The compositions comprise the following ingre- 15 eollheht 0f P e P P Q h 111 this lhehher glasses dients; to 0 e percent h id p1 0), to having a relatively good devrtrrfication resistance are ob- 70 wt. percent P 0 and 7.2-11 wt. percent of at least tamed- The prlor art leadrhosphafe glasses contain y one f the Oxides of magnesium, l i strontium, small amounts of lead oxrde, i.e., in these known glasses barium and aluminum. The glass compositions are chemlead oxlde is h a Principal Component, as it is (1600! ding ically resistant, resistant to devitrification, stable to 20 t0 the l h s Serves h y t0 eohreet the Optical weathering and corrosion and have the desired transmis- P p feffaehoh Whleh for thls yp of flint sion in the short wave length blue range of the spectrum. glass Constitutes ower refractive indexes.

The following table sets forth examples of optical glass according to the invention. The components are The invention relates to optical glass and more par- 25 given in Pereehtages y Weight- The Optical Values are ticularly to optical flint glass on a lead phosphate basis. also reported.

TABLE A B C D E F G H I J The partial dispersions of flint glass containing lead The glasses are more color-free than comparable lead phosphate differ decidedly from silicate-base glasses in silicate glasses and have good acid and weather resistance; that they decrease transmission through the short wavetherr susceptibility to staining corresponds to Class 1.

length blue range of the visible spectrum. In the design The following example will further illustrate the nature of optical systems, this represents an undesirable variant of th1s invention and the method for preparing the novel in the optical properties of the resulting glass. Heretofore glass compositions but the invention is not restricted to optical flint glass production has been limited substanthe example.

tially to lead silicate-base glass because of their greater EXAMPLE ease of manufacture.

It is an object of the present invention to provide \A 1000 h batch Containing 448 441 2 5; multi-component flint glass compositions on a lead phos- 52 Bao the form of the C responding carbonates) phate basis and method of making the Same having the and 1? g. of A1 9 were placed in a crucible of refractory desired properties of chemical resistance, resistance to mammal (eeramle) heated to a perature of between devitrification, stability to weathering and corrosion and about 930 and in an tri r gas heated furtransmission in the Shortwave length blue range of the mace. After the batch had melted, it was clarified for one speemmh hour at about 1020-1070 C. The glass batch was stirred Another object of the invention is to provide glass 55 f aboutol hour While the furnace Cooled dOWn to compositions having the above characteristics which will about 780 The cooled glass was then Poured at about have good optical properties and which may be cast, 650-680 C. into a preheated iron mold. The glass Was molded, annealed fused and otherwise processed by the thereafter transferred to a lehr that had been set at a usual glass manipulation mechanisms usual in the at temperature of about 370 C. and was cooled at a rate Still another object of the invention is the provision of of about 70 Per hour down to room temperatureflint glass compositions on a lead phosphate basis having What clalmed 1S:

a high transmission for visible light in the wavelength 1. An optrcal glass characterized 1n that it is resistant b1 a fth t to chemrcals, Weathering, devitrification and has a high o h objects and advantages f h invention will transmission of visible light in the short wavelength blue m apparent f th f u i d i i range of the spectrum, having the following composition: The glass compositions in accordance with the inven- 39.7 wt. perce t P O, Percent P tion consist of the following ingredients: 24.2 to 55 wt. cent A1 0 51.9 wt. percent P 0 2. An optical glass characterized in that it is resistant to chemicals, weathering, devitrification and has a high transmission of visible light in the short wavelength blue range of the spectrum, having the following com position: 42.8 wt. percent PbO, 7.8 wt. percent BaO, 2.9 wt. percent A1 0 46.5 wt. percent P 0 3. An optical glass characterized in that it is resistant to chemicals, weathering, devitrification and has a high transmission of visible light in the short wavelength blue range of the spectrum, having the following composition: 48.8 wt. percent PbO, 3.9 wt. percent A1 0 and 47.3 wt. percent P 0 4. \An optical glass characterized in that it is resistant to chemicals, weathering, devitrification and has a high transmission of visible light in the short wavelength blue range of the spectrum, having the following composition: 29.4 wt. percent PbO, 1.2 wt. percent CaO, 3.0 wt. percent Al O and 67.4 wt. percent P 0 5. An optical glass characterized in that it is resistant to chemicals, weathering, devitrification and has a high transmission of visible light in the short wavelength blue range of the spectrum, having the following composition: 24.2 wt. percent PbO, 1.2 wt. percent MgO, 1.3 wt. percent C aO, and 66.3 wt. percent P 0 6. An optical glass characterized in that it is resistant to chemicals, weathering, devitrification and has a high transmission of visible light in the short wavelength blue range of the spectrum, having the following composition: 25.3 wt. percent PbO, 1.2 wt. percent MgO, 1.5 wt. percent BaO, 2.0 wt. percent A1 0 70.0 wt. percent P 0 References Cited UNITED STATES PATENTS 1,654,404 12/1927 Blumenberg 106 47 2,031,958 2/1936 Kaufmann et a1 106-47 2,381,925 8/1945 Pincus 106--47 2,441,853 5/1948 Stanworth 106-47 2,684,304 7/1954 Weissenberg et al 106-47 2,723,203 11/1955 Weissenberg et al. 106-47 2,996,390 8/1961 Weissenberg et al. 106-47 FOREIGN PATENTS 1,805,719 1955 France 106-47 HELEN M. MCCARTHY, Primary Examiner l L. Signed and sealed this 7th day of December 1 971 lnwrnt'orfii) Walge; Jahn It is certified that error appears in the a:)ovc1 lc:ntiflcd puLc-nt and Lhnt: said LCLLCI'S Patent are hereby corrected as shown below:

Col. 1, line 3, the name of assignor should be JENAerand not "JENaer";

line 17, "7.2-11" should be l.2-ll

line 41, "short wave-length should be short-wave length-- line 49, "multi-component" should be multiplecornponent Col. 2 in the table under the heading "K" 4th item down "7 .5" is shown as 1 .5 line 64 "wavelength" should be wave length Col. 3, line 3, "wa velength" should be wave length line 9, "wavelength" should be wave length line 15, "wavelength" should be wave length line 21, "wavelength" should be wave length .Col. 4, line 3, "wavelength" should be wave length line 4, the reference to French Patent should be "1,085, 719" and not 1,805 ,719

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Acting Commissioner of Patents 

